A segment of wire vibrates with a fundamental frequency of $450\;Hz$ under a tension of 9 Kg wt. Then tension at which the fundamental frequency of the same wire becomes 900 Hz is

Question

$$\begin {array} {1 1} (a)\;36\;kg-wt & \quad (b)\;27\;kg-wt \\ (c)\;18 kg-wt & \quad (d)\;72\;kg-wt \end {array}$$